The increasing availability of molecular tools is facilitating marker-assisted
selection (MAS) in plant improvement programs. The objectives of this research were
to: 1) populate the framework buffelgrass genome map with additional molecular
markers, 2) develop polymerase chain reaction (PCR)-based markers from selected,
informative restriction fragment length polymorphism (RFLP) markers on the
buffelgrass genome map, and 3) increase marker resolution near the locus conferring
apomixis (PApo1). Buffelgrass [Pennisetum ciliare (L.) Link syn. Cenchrus ciliaris L.]
(2n=4x=36), a highly polymorphic, apomictic, perennial forage grass, is well-suited for
genetic linkage analyses. One hundred and seventy one probes from an apomictic,
spikelet-specific, complementary deoxyribonucleic acid (cDNA) library and 70
expressed sequence tag simple sequence repeats (EST-SSRs) from apomictic pistil
cDNAs were evaluated and added to the framework buffelgrass genome map. The
improved linkage map contains 851 markers from 11 grass species and covers
approximately 80-85% of the buffelgrass genome. Two RFLPs from the buffelgrass
genome map were converted to PCR-based markers for both the identification of hybrids and quantification of sexual versus apomictic reproduction. A gel-free, high-throughput
technique was developed to analyze these markers directly in 96-well plates. Five
additional markers were placed onto the buffelgrass linkage group with the PApo1
apomixis locus through comparative mapping of candidate orthologs from the sorghum
genome map and bulked-segregant analysis of amplified-fragment-lengthpolymorphisms
(BSA-AFLP). Increasing the mapping population size did not increase
map resolution in the PApo1 region. Association mapping revealed that the
recombination suppression near PApo1 is moderate and would complicate comparative
map-based cloning efforts of the orthologous region in sorghum.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/2656 |
| Date | 01 November 2005 |
| Creators | Jessup, Russell William |
| Contributors | Burson, Byron L., Hussey, Mark A. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 486505 bytes, electronic, application/pdf, born digital |
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